Analog/digital map conversion and cartographic information content changes

The mutual conversion between analog map and digital map is two main contents of the study on digital mapping, which is the production of paper map and spatial data. The visualization of spatial data is the common problem that the spatial data application system confronted, so it is practically meaningful to study the mutual conversion between analog map and digital map. The paper indicates the two processes of the decrease and increase of cartographic information content in two conversions, educes a cartographic information transfer model based on Shannon communication system model, and makes a deep quantitative and qualitative analysis on the decrease and increase of cartographic information in analog/digital conversion in terms of information theory and cartographic theory. The paper also shows that the accuracy of cartographic information should be improved in analog-digital conversion and the information content transformed should be increased to the fullest extent in digital-analog conversion. The corresponding disposal is respectively given for the two processes.